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urfd/reflector/DCSProtocol.cpp

478 lines
14 KiB

// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
// urfd -- The universal reflector
// Copyright © 2021 Thomas A. Early N7TAE
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
#include <string.h>
#include "Global.h"
#include "DCSClient.h"
#include "DCSProtocol.h"
////////////////////////////////////////////////////////////////////////////////////////
// operation
bool CDcsProtocol::Initialize(const char *type, const EProtocol ptype, const uint16_t port, const bool has_ipv4, const bool has_ipv6)
{
// base class
if (! CProtocol::Initialize(type, ptype, port, has_ipv4, has_ipv6))
return false;
// update time
m_LastKeepaliveTime.start();
// done
return true;
}
////////////////////////////////////////////////////////////////////////////////////////
// task
void CDcsProtocol::Task(void)
{
CBuffer Buffer;
CIp Ip;
CCallsign Callsign;
char ToLinkModule;
std::unique_ptr<CDvHeaderPacket> Header;
std::unique_ptr<CDvFramePacket> Frame;
// handle incoming packets
#if DSTAR_IPV6==true
#if DSTAR_IPV4==true
if ( ReceiveDS(Buffer, Ip, 20) )
#else
if ( Receive6(Buffer, Ip, 20) )
#endif
#else
if ( Receive4(Buffer, Ip, 20) )
#endif
{
// crack the packet
if ( IsValidDvPacket(Buffer, Header, Frame) )
{
// callsign muted?
if ( g_GateKeeper.MayTransmit(Header->GetMyCallsign(), Ip, EProtocol::dcs, Header->GetRpt2Module()) )
{
OnDvHeaderPacketIn(Header, Ip);
OnDvFramePacketIn(Frame, &Ip);
}
}
else if ( IsValidConnectPacket(Buffer, &Callsign, &ToLinkModule) )
{
std::cout << "DCS connect packet for module " << ToLinkModule << " from " << Callsign << " at " << Ip << std::endl;
// callsign authorized?
if ( g_GateKeeper.MayLink(Callsign, Ip, EProtocol::dcs) && g_Reflector.IsValidModule(ToLinkModule) )
{
// valid module ?
if ( g_Reflector.IsValidModule(ToLinkModule) )
{
// acknowledge the request
EncodeConnectAckPacket(Callsign, ToLinkModule, &Buffer);
Send(Buffer, Ip);
// create the client and append
g_Reflector.GetClients()->AddClient(std::make_shared<CDcsClient>(Callsign, Ip, ToLinkModule));
g_Reflector.ReleaseClients();
}
else
{
std::cout << "DCS node " << Callsign << " connect attempt on non-existing module" << std::endl;
// deny the request
EncodeConnectNackPacket(Callsign, ToLinkModule, &Buffer);
Send(Buffer, Ip);
}
}
else
{
// deny the request
EncodeConnectNackPacket(Callsign, ToLinkModule, &Buffer);
Send(Buffer, Ip);
}
}
else if ( IsValidDisconnectPacket(Buffer, &Callsign) )
{
std::cout << "DCS disconnect packet from " << Callsign << " at " << Ip << std::endl;
// find client
CClients *clients = g_Reflector.GetClients();
std::shared_ptr<CClient>client = clients->FindClient(Ip, EProtocol::dcs);
if ( client != nullptr )
{
// remove it
clients->RemoveClient(client);
// and acknowledge the disconnect
EncodeConnectNackPacket(Callsign, ' ', &Buffer);
Send(Buffer, Ip);
}
g_Reflector.ReleaseClients();
}
else if ( IsValidKeepAlivePacket(Buffer, &Callsign) )
{
//std::cout << "DCS keepalive packet from " << Callsign << " at " << Ip << std::endl;
// find all clients with that callsign & ip and keep them alive
CClients *clients = g_Reflector.GetClients();
auto it = clients->begin();
std::shared_ptr<CClient>client = nullptr;
while ( (client = clients->FindNextClient(Callsign, Ip, EProtocol::dcs, it)) != nullptr )
{
client->Alive();
}
g_Reflector.ReleaseClients();
}
else if ( IsIgnorePacket(Buffer) )
{
// valid but ignore packet
//std::cout << "DCS ignored packet from " << Ip << std::endl;
}
else
{
// invalid packet
std::string title("Unknown DCS packet from ");
title += Ip.GetAddress();
Buffer.Dump(title);
}
}
// handle end of streaming timeout
CheckStreamsTimeout();
// handle queue from reflector
HandleQueue();
// keep client alive
if ( m_LastKeepaliveTime.time() > DCS_KEEPALIVE_PERIOD )
{
//
HandleKeepalives();
// update time
m_LastKeepaliveTime.start();
}
}
////////////////////////////////////////////////////////////////////////////////////////
// streams helpers
void CDcsProtocol::OnDvHeaderPacketIn(std::unique_ptr<CDvHeaderPacket> &Header, const CIp &Ip)
{
// find the stream
auto stream = GetStream(Header->GetStreamId());
if ( stream )
{
// stream already open
// skip packet, but tickle the stream
stream->Tickle();
}
else
{
// no stream open yet, open a new one
CCallsign my(Header->GetMyCallsign());
CCallsign rpt1(Header->GetRpt1Callsign());
CCallsign rpt2(Header->GetRpt2Callsign());
// find this client
std::shared_ptr<CClient>client = g_Reflector.GetClients()->FindClient(Ip, EProtocol::dcs);
if ( client )
{
// get client callsign
rpt1 = client->GetCallsign();
// and try to open the stream
if ( (stream = g_Reflector.OpenStream(Header, client)) != nullptr )
{
// keep the handle
m_Streams[stream->GetStreamId()] = stream;
}
}
// release
g_Reflector.ReleaseClients();
// update last heard
g_Reflector.GetUsers()->Hearing(my, rpt1, rpt2);
g_Reflector.ReleaseUsers();
}
}
////////////////////////////////////////////////////////////////////////////////////////
// queue helper
void CDcsProtocol::HandleQueue(void)
{
while (! m_Queue.IsEmpty())
{
// get the packet
auto packet = m_Queue.Pop();
// get our sender's id
const auto module = packet->GetPacketModule();
// check if it's header and update cache
if ( packet->IsDvHeader() )
{
// this relies on queue feeder setting valid module id
// m_StreamsCache[module] will be created if it doesn't exist
m_StreamsCache[module].m_dvHeader = CDvHeaderPacket((const CDvHeaderPacket &)*packet.get());
m_StreamsCache[module].m_iSeqCounter = 0;
}
else
{
// encode it
CBuffer buffer;
if ( packet->IsLastPacket() )
{
EncodeLastDCSPacket(m_StreamsCache[module].m_dvHeader, (const CDvFramePacket &)*packet.get(), m_StreamsCache[module].m_iSeqCounter++, &buffer);
}
else if ( packet->IsDvFrame() )
{
EncodeDCSPacket(m_StreamsCache[module].m_dvHeader, (const CDvFramePacket &)*packet.get(), m_StreamsCache[module].m_iSeqCounter++, &buffer);
}
// send it
if ( buffer.size() > 0 )
{
// and push it to all our clients linked to the module and who are not streaming in
CClients *clients = g_Reflector.GetClients();
auto it = clients->begin();
std::shared_ptr<CClient>client = nullptr;
while ( (client = clients->FindNextClient(EProtocol::dcs, it)) != nullptr )
{
// is this client busy ?
if ( !client->IsAMaster() && (client->GetReflectorModule() == module) )
{
// no, send the packet
Send(buffer, client->GetIp());
}
}
g_Reflector.ReleaseClients();
}
}
}
}
////////////////////////////////////////////////////////////////////////////////////////
// keepalive helpers
void CDcsProtocol::HandleKeepalives(void)
{
// DCS protocol sends and monitors keepalives packets
// event if the client is currently streaming
// so, send keepalives to all
CBuffer keepalive1;
EncodeKeepAlivePacket(&keepalive1);
// iterate on clients
CClients *clients = g_Reflector.GetClients();
auto it = clients->begin();
std::shared_ptr<CClient>client = nullptr;
while ( (client = clients->FindNextClient(EProtocol::dcs, it)) != nullptr )
{
// encode client's specific keepalive packet
CBuffer keepalive2;
EncodeKeepAlivePacket(&keepalive2, client);
// send keepalive
Send(keepalive1, client->GetIp());
Send(keepalive2, client->GetIp());
// is this client busy ?
if ( client->IsAMaster() )
{
// yes, just tickle it
client->Alive();
}
// check it's still with us
else if ( !client->IsAlive() )
{
// no, disconnect
CBuffer disconnect;
EncodeDisconnectPacket(&disconnect, client);
Send(disconnect, client->GetIp());
// remove it
std::cout << "DCS client " << client->GetCallsign() << " keepalive timeout" << std::endl;
clients->RemoveClient(client);
}
}
g_Reflector.ReleaseClients();
}
////////////////////////////////////////////////////////////////////////////////////////
// packet decoding helpers
bool CDcsProtocol::IsValidConnectPacket(const CBuffer &Buffer, CCallsign *callsign, char *reflectormodule)
{
bool valid = false;
if ( Buffer.size() == 519 )
{
callsign->SetCallsign(Buffer.data(), 8);
callsign->SetCSModule(Buffer.data()[8]);
*reflectormodule = Buffer.data()[9];
valid = (callsign->IsValid() && IsLetter(*reflectormodule));
}
return valid;
}
bool CDcsProtocol::IsValidDisconnectPacket(const CBuffer &Buffer, CCallsign *callsign)
{
bool valid = false;
if ((Buffer.size() == 11) && (Buffer.data()[9] == ' '))
{
callsign->SetCallsign(Buffer.data(), 8);
callsign->SetCSModule(Buffer.data()[8]);
valid = callsign->IsValid();
}
else if ((Buffer.size() == 19) && (Buffer.data()[9] == ' ') && (Buffer.data()[10] == 0x00))
{
callsign->SetCallsign(Buffer.data(), 8);
callsign->SetCSModule(Buffer.data()[8]);
valid = callsign->IsValid();
}
return valid;
}
bool CDcsProtocol::IsValidKeepAlivePacket(const CBuffer &Buffer, CCallsign *callsign)
{
bool valid = false;
if ( (Buffer.size() == 17) || (Buffer.size() == 15) || (Buffer.size() == 22) )
{
callsign->SetCallsign(Buffer.data(), 8);
valid = callsign->IsValid();
}
return valid;
}
bool CDcsProtocol::IsValidDvPacket(const CBuffer &Buffer, std::unique_ptr<CDvHeaderPacket> &header, std::unique_ptr<CDvFramePacket> &frame)
{
uint8_t tag[] = { '0','0','0','1' };
if ( (Buffer.size() >= 100) && (Buffer.Compare(tag, sizeof(tag)) == 0) )
{
// get the header
header = std::unique_ptr<CDvHeaderPacket>(new CDvHeaderPacket((struct dstar_header *)&(Buffer.data()[4]), *((uint16_t *)&(Buffer.data()[43])), 0x80));
// get the frame
frame = std::unique_ptr<CDvFramePacket>(new CDvFramePacket((SDStarFrame *)&(Buffer.data()[46]), *((uint16_t *)&(Buffer.data()[43])), Buffer.data()[45]));
// check validity of packets
if ( header && header->IsValid() && frame && frame->IsValid() )
return true;
}
return false;
}
bool CDcsProtocol::IsIgnorePacket(const CBuffer &Buffer)
{
uint8_t tag[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, };
if ( Buffer.size() == 15 && Buffer.Compare(tag, sizeof(tag)) == 0 )
return true;
return false;
}
////////////////////////////////////////////////////////////////////////////////////////
// packet encoding helpers
void CDcsProtocol::EncodeKeepAlivePacket(CBuffer *Buffer)
{
Buffer->Set(GetReflectorCallsign());
}
void CDcsProtocol::EncodeKeepAlivePacket(CBuffer *Buffer, std::shared_ptr<CClient>Client)
{
uint8_t tag[] = { 0x0A,0x00,0x20,0x20 };
Buffer->Set((uint8_t *)(const char *)GetReflectorCallsign(), CALLSIGN_LEN-1);
Buffer->Append((uint8_t)Client->GetReflectorModule());
Buffer->Append((uint8_t)' ');
Buffer->Append((uint8_t *)(const char *)Client->GetCallsign(), CALLSIGN_LEN-1);
Buffer->Append((uint8_t)Client->GetCSModule());
Buffer->Append((uint8_t)Client->GetCSModule());
Buffer->Append(tag, sizeof(tag));
}
void CDcsProtocol::EncodeConnectAckPacket(const CCallsign &Callsign, char ReflectorModule, CBuffer *Buffer)
{
uint8_t tag[] = { 'A','C','K',0x00 };
uint8_t cs[CALLSIGN_LEN];
Callsign.GetCallsign(cs);
Buffer->Set(cs, CALLSIGN_LEN-1);
Buffer->Append((uint8_t)' ');
Buffer->Append((uint8_t)Callsign.GetCSModule());
Buffer->Append((uint8_t)ReflectorModule);
Buffer->Append(tag, sizeof(tag));
}
void CDcsProtocol::EncodeConnectNackPacket(const CCallsign &Callsign, char ReflectorModule, CBuffer *Buffer)
{
uint8_t tag[] = { 'N','A','K',0x00 };
uint8_t cs[CALLSIGN_LEN];
Callsign.GetCallsign(cs);
Buffer->Set(cs, CALLSIGN_LEN-1);
Buffer->Append((uint8_t)' ');
Buffer->Append((uint8_t)Callsign.GetCSModule());
Buffer->Append((uint8_t)ReflectorModule);
Buffer->Append(tag, sizeof(tag));
}
void CDcsProtocol::EncodeDisconnectPacket(CBuffer *Buffer, std::shared_ptr<CClient>Client)
{
Buffer->Set((uint8_t *)(const char *)Client->GetCallsign(), CALLSIGN_LEN-1);
Buffer->Append((uint8_t)' ');
Buffer->Append((uint8_t)Client->GetCSModule());
Buffer->Append((uint8_t)0x00);
Buffer->Append((uint8_t *)(const char *)GetReflectorCallsign(), CALLSIGN_LEN-1);
Buffer->Append((uint8_t)' ');
Buffer->Append((uint8_t)0x00);
}
void CDcsProtocol::EncodeDCSPacket(const CDvHeaderPacket &Header, const CDvFramePacket &DvFrame, uint32_t iSeq, CBuffer *Buffer) const
{
uint8_t tag[] = { '0','0','0','1' };
struct dstar_header DstarHeader;
Header.ConvertToDstarStruct(&DstarHeader);
Buffer->Set(tag, sizeof(tag));
Buffer->Append((uint8_t *)&DstarHeader, sizeof(struct dstar_header) - sizeof(uint16_t));
Buffer->Append(DvFrame.GetStreamId());
Buffer->Append((uint8_t)(DvFrame.GetPacketId() % 21));
Buffer->Append((uint8_t *)DvFrame.GetCodecData(ECodecType::dstar), 9);
Buffer->Append((uint8_t *)DvFrame.GetDvData(), 3);
Buffer->Append((uint8_t)((iSeq >> 0) & 0xFF));
Buffer->Append((uint8_t)((iSeq >> 8) & 0xFF));
Buffer->Append((uint8_t)((iSeq >> 16) & 0xFF));
Buffer->Append((uint8_t)0x01);
Buffer->Append((uint8_t)0x00, 38);
}
void CDcsProtocol::EncodeLastDCSPacket(const CDvHeaderPacket &Header, const CDvFramePacket &DvFrame, uint32_t iSeq, CBuffer *Buffer) const
{
EncodeDCSPacket(Header, DvFrame, iSeq, Buffer);
(Buffer->data())[45] |= 0x40;
}

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